Voltage splitting circuit



Patented Dec. 12, 1950 UNITED STATE-S PATENT oFFicsYf,

VOLTAGE SFLITTING CIRCUIT Jay W. Picking, Cleveland, and Walter Brown, Cleveland Heights, Ohio Application October 8, 1948, Serial No. 53,558

23 Claims. 1 The invention relates in general to voltage dividing or voltage splitting circuits and more particularly to voltage splitting circuits that split an input voltage at a definite value.

An object of the invention is to provide a voltage splitting circuit that will split an incoming,

variable signal voltage at a definite magnitude as opposed to voltage dividers that divide an incoming variable signal Voltage at a definite proportion of the incoming voltage.

Another object of the invention is to provide a voltage splitting circuit for providing two outvput voltages, one of which varies directly for low second output voltage remaining at the reference value for input voltages below the reference value and varying inversely with the input voltage for values thereof above the reference value.

Yet another object of the invention is to provide a circuit performing the functions as stated immediately above wherein the second output voltage varies inversely as a nonlinear function approaching a hyperbolic function of the input voltage for values thereof above the reference value.

A still further object of the invention is to pro vide a voltage splitting circuit that includes rectifier devices which will conduct current at a definite reference value and thus an output voltage may eifect a transition at this definite value from a condition of varying in accordance with the input signal voltage to a condition of remain- 'ing substantially constant, and a second output voltage vice versa.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in con- -junction with the accompanying drawings, in

which:

Figure 1 is an electrical circuit diagram of a basic circuit for accomplishing voltage splitting Y of an input signal voltage into two output voltage Figure 2 is a circuit diagram of the preferred embodiment of the invention incorporating certain improvements over the circuit of Figure l; and

input Figure 3 is a graph showing the voltages obtainable from the circuits of Figures 1 and'2.

The basic circuit as in Figure 1 shows a source of signal direct voltage II having positive and negative terminals l2 and I3, respectively. The signal direct voltage source H has a variable output, and this variable output may be provided in any suitable manner. For purposes of illustration, this variation is provided by a potentiometer l4 having a variable tap l5 and being connected across the positive and negative terminals l2 and It; A reference direct voltage source is is shown as having positive and negative terminals ii and !8, respectively. Connected across this reference direct voltage source it is an impedance shown as a resistance H) for obtaining reference voltages from this reference I First, second and third leled between the variable tap it and the second reference terminal 2! of the resistance 19. -The first branch path 2i includes an impedance device 2t and a rectifier device 2'; with a first output terminal as connected therebetween, The

second branch path 25 similarly includes an impedance device 25 and a rectifier device 30 with a second output terminal 35 connected therebetwecn. The first rectifier device 21 has an anode 32 and a cathode 33 for conducting electron current between'the' second reference terminal 2i and the variable tap It. In a similar fashion, the'second rectifier device 39 has an anode 3 and a cathode 535 for passing electron current between the second reference terminal 2! and the variable tap it. 1

The operation of the circuit of Figure l is such as to obtain first and second output voltages I which have a definite transition value as'determined by a reference voltage value. A first output voltage e1 is obtained between the first output terminal 28 and the first reference terminal 20 of the reference direct voltage source IS. A second output voltage e2 is obtained between the second output terminal 3! and the third reference terminal 22 of the reference direct voltage o from the referencedirect voltage sourceltbesource IS. A reference voltagecn is obtained the value of the impedance device 29.

third reference terminals 2| and 22.

tween the first and second reference terminals 2|] and 2|. The signal direct voltage source ii is shown as being variable by means of the variable tap I5, to develop a signal voltage 6s between the variable tap I5 and the negative terminal it. To obtain the full usefulness from this circuit, the signal voltage es from the signal direct voltage source should be capable of exceedin the value of the reference voltage obtained between the first and second reference terminals 20 and 2 I. When the rectifier device 21 is not passing any current, the impedance of this rectifier device 21 will be quite high, and will be quite high relative to the value of the impedance device 26. It may thus be seen that the potential of the first output terminal 28 will be essentially that of the potential of the variable tap I5. Since the first reference terminal '20 is connected to the negative terminal I3 of the signal direct voltage source I I, the first output voltage 61 will vary directly and be substantially equal to the signal voltage 65 obtained from. the potentiometer M by the variable tap I5 for all values of the signal voltage 6s below the value of the reference voltage ea. When the variable tap I5 obtains a signal voltage es from the potentiometer I4 that isof a value in excess of theva'lueof the reference voltage ea, then the rectifier device 21' will conduct current. When this rectifier device 2T is conducting current it will have a low value of impedance relative to thevalue of the impedance device 26, and hence the first output terminal 28 may be considered asbeing efi'ectively tied to the second reference terminal 21, and will thus remain substantially at the' potential of the second reference terminal II. It will, therefore, be seen that for values of thesignal voltage in excess of the reference voltage en the first output voltage e1 will remain sub- 'stantially at a given value which is determined by the value of the reference voltage 8R and, in 1 this case, will equal the voltage en.

The second output voltage e2 is obtained between the second output terminal 3! and the third reference terminal 22. When the signal voltage es is less than the reference voltage on, the rectifier device 30 will not conduct and, hence, its impedance will be considerably greater than Under these conditions, the second output terminal 31 will-have a potential corresponding to the potential of the second reference terminal 2!. The second output voltage 62 will therefore be that of the voltage existing between the second and When the signal voltage es exceeds the reference voltage en, the rectifier device all will conduct current and, hence, the impedancethereof will be considerably lower than the impedance of the impedance device '29. For these conditions, the secvice 29. This increasing voltage drop across the impedance device 29 will be in opposition to the voltage obtained from the resistance i9 between the second and third reference terminals 2| and 22 and hence the second output voltage will continue to decrease as the signal voltage es increases. It may thus be seen that the second output voltage e2 varies in accordance with the sig nal voltage es, which variation is an inverse variation.

The first output voltage e1 is connected to a first electric power converter 56, and the second output voltage e2 is connected to a second electric power converter 5?. The first and second electric power converters 56 and 51 are adapted to utilize the respective output voltages in the control of a load of these converters. The first electric power converter 553 has been shown as being connected to a motor armature 58 which may be a direct current motor armature. The second electric power converter 51 has been shown as being connected to an inductance 59 having an iron core. The inductance 59 may be the field winding of the motor armature 58.

The graph of Figure 3 may be referred to as an aid in understanding the variations in the first and second output voltages with variations of signal voltage'es. For purposes of illustration, the value of the reference voltage ea between the first and second reference terminals 2-0 and 2! has been taken as volts with a maximum value of signal voltage es as being 200 volts. It will be seen from looking at the graph of Figure 3 that the first and second output voltages c1 and 22 have. a definite transition value or a knee in the curve at a value of signal voltage equal to the value of the reference voltage ea, which in this case has been taken as 100 volts. The first output voltage e1 between the first output terminal 28 and the first reference terminal 2i] varies directly as a substantially linear function of the signal voltage or until the reference voltage value is reached. When the signal voltage 65 equals the value of the reference voltage en, the rectifier 21. conducts and from there on the potential of the first output terminal 28. is held substantially at the potential of the second reference terminal 2!. Therefore, the first output voltage e1 remains substantially constant at a given value, in this case 100 volts, for all values of the signal voltage 65 in excess of the value of the reference voltage en.

The second output voltage e2 remains substantially constant at a given value for all values of the signal voltage 65 below the value of the reference voltage era. The value of the-second output voltage 62 under these conditions is the value of the voltage between the second and third reference terminals 21 and 22. This may sometimes be referred to as a second reference voltage, and for purposes of illustration, this has also. been shown as being equal to 100 volts. When the signal voltage 65 exceeds the value of the reference voltage en, the rectifier 30 will conduct, and hence the current passing through this rectifier will cause'a voltage drop across the impedance device 253 which causes the second output voltage 62 to decrease.

The circuit of Figure 2 is an improvement over the circuit of Figure l, but in general retains-the same basic operation. The signal direct voltage source I I again supplies a variable signal voltage 65 between the variable tap I5 and the negative terminal I3 of the voltage source II. The variable feature has been indicated as being obtained from the potentiometer I4 but it is obvious that this is by way of illustration only and any form of variable signal voltage may be used. The reference direct voltage source It has again been shown as having a resistance I9 connected across the positive and negative terminals I! and I8 thereof. The first, second and third reference terminals 20, 2| and 22 have again been shown and additionally fourth and fifth reference terminals 36 and 31, respectively, have been shown as variable taps on this resistance [9. The circuit includes first and second branch paths 38 and 39 paralleled between the variable tap l5 and the second reference terminal 2|. The first branch path 38 includes a thermionic tube 43 having an anode 4| and a cathode 42. The anode resistor 43 is connected in series with the anode 4! with the first output terminal connected therebetween. A cathode impedance 53 and shunting switch 54 are connected between the cathode 42 and terminal 2|.

The second branch path 39 includes a thermionic tube 44 having an anode 45, a cathode 46 and a control grid 41. A cathode resistor 48 is connected to the cathode 46 with a third output terminal connected therebetween. First and second grid biasing impedances t9 and 53 are serially connected between the variable tap I5 and the fifth reference terminal 31. The control grid 41 is connected to the juncture 5! of the first and second grid biasing impedances s9 and 5!) by a grid current-limiting resistance 52.

The operation of the circuit of Figure 2 is basically the same as that of the operation of the circuit of Figure l. The reference voltage ca is again obtained between the first and second reference terminals 20 and 2!. When the value of the signal voltage e5 exceeds the value of the ref erence voltage ea the thermionic tubes 4%! and 44 will conduct current. A first output voltage e1 is obtained between the first output terminal 23 and the first reference terminal and a third output voltage 63 is obtained between the third output terminal 55 and the third reference terminal 22. A fourth output voltage a; may be obtained between the first output terminal 28 and the fourth reference terminal 36. The fourth reference terminal 36 has been shown as having a potential that is positive relative to the potential of the first reference terminal 28. The fourth output voltage 64 is shown as being connected to the first electric power converter 55 which supplies electric power to the motor armature 58 and the third output voltage ex is shown as being connected to the second electric power converter 51 for control of the energy supplied to the inductance 59.

The graph of Figure 3 may be referred to as an aid in understanding the operation of the circuit of Figure 2. The operation of the circuit shall first be described with the shunting switch 554 closed to remove the cathode impedance 53 from the circuit. For values of signal voltage es below the value of the reference voltage era, the first and fourth output voltages er and or will vary directly as a substantially linear function of the signal voltage es. The reference voltage on determines the transition value at which the output voltages have a knee in the curve. The graph of the first output voltage 61 is the same for the Figure 2 as for the Figure 1. Since the fourth output voltage cr is obtained between the first output terminal 28 and the fourth reference terminal 36, the fourth output voltage e4 will have the curve thereof displaced from the curve of the first output voltage e1 by the potential difference between the first and fourth reference terminals 20 and 3E.

The third output voltage e3 will be the same as the second output voltage e2 obtained from the circuit of Figure 1 for values of the signal volttage 68 less than the value of the reference voltage en. Since the second branch path 39 has included 6 therein a thermionic tube which includes a control grid 41, the third output voltage e3 will not coincide with the second output voltage e2 obtained from the circuit of Figure 1 when the signal voltage exceeds the reference voltage en. The thermionic tube 44 is shown as a triode but may be other forms of thermionic tubes having control grids. The purpose of using a triode for V the thermionic tube 44 is to obtain a non-linear characteristic of the third output voltage eg when the signal voltage es exceeds the reference volt- -'age ea.

An application of this voltage splitting circuit is in the control of a generator excited direct current motor control system wherein it is desired to control the fields of both the direct cur- 'rent generator and direct current motor. Another application is to control separate electric converters supplying power to the armature and field, respectively, of a direct current motor. In either of the above cases, the control would be of the armature and field energization of a direct current motor. In the circuit of Figure 2, the inductance 59 may be the field winding of the motor armature 58 and, hence, the circuit of Figure 2 which incorporates the control grid tube '44 may have special application. As is well known, the speed of the direct current motor may be governed by the voltage applied to the motor armature and may further be governed by the field excitation of the direct current motor. In customary speed control of the direct current motor in such a system, it is usual to vary the generator field excitation, or the output of the electric converter supplying the armature, from zero to a given value to obtain any speed of the direct current motor between zero and base speed. For speeds of the motor above base speed, the field of the motor is weakened from its normal excitation. The first and second output voltages -e1 and e2 of the circuit of Figure 1 will provide the requisite control for the generator field or armature converter and for the motor field, respectively. The circuit of Figure 2 provides an improvement over the circuit of Figure 1 since it provides a nonlinear variation characteristic in the third output voltage. This third output voltage e3 would be that used to control the motor field. Since the speed of a direct current motor varies as a function of a constant divided by the field flux, it will be seen that variation of motor speed with field flux is a hyperbolic function. The field fiux varies with the field voltage over a part of the working range as a linear function though it departs thereafter from linearity, be-

cause of field saturation. Accordingly, the field voltage and motor speed vary directly as a nonlinear function approaching a hyperbolic function. Consequently, since the second output voltage of Figure l varies linearly with the signal input voltage, the motor speed would vary in a 'manner approaching a hyperbolic function of the signal input voltage for motor speed above 'base speed. This condition is undesirable because given increments of signal voltage cause increasingly larger changes of motor speed as the motor speed increases above base speed. T0

at least partially compensate for this roughly hyperbolic characteristic of motor speed versus result in a motor speed-signal voltage curve that iszmorenearly linear. The-control grid 41 is biased-positively relative to the cathode 46 for signali voltages at and slightly above transferor the transition point, and, hence, the tube 44 will conduct a. maximum current when the signal voltage-e exceeds the reference voltage en. However, as'the signal voltage es increases, the increase1in the current passed by the tube 44 will cause increasing voltage drops across the cathode resistor 48.: This will cause a self-biasing action which will bias the grid 41 negatively relative to the cathode 46 thus increasing the impedance of the thermionic tube 44. The third output terminal 55 .will thusnot be exactly tiedto the potential :of 'the variable tap IE-but will differ in potential by thevoltage'drop across the tube 44. This causes'thennonlinear characteristic of the third output voltage ea when the signal voltage 65 exceeds :the reference voltage ea.

In the branchcircuit 38, when the switch 54-is opened, the cathode impedance 53 will be inserted in the circuit betweenthe cathode 42 and the seccndreference terminal 2 l. Such a cathode impedance would cause a voltage drop to exist thereacross-when the tube'40 isconducting current and thusthe curve of the-voltage @1 would have a rising characteristic as shown by the curve ei 1 when the'signal voltage 65 exceeds the referencewoltage-ea. This may be desirable in some cases where a rising characteristic of the first output *voltage is beneficial.

Thecircuits of Figures -1 and 2 have been shownsas-having the negative terminals of the reference-and 'signal voltage sources interconnected- By inverting-the entire circuit, it will be seen that the positive terminals of these signal and reference-voltage sources may be interconnected. Toachieve-such an inverted circuit, the rectifiers in the branchlpaths 2L and 25 or 38 and 39 should be inverted so that the anodes of the rectifier-s -will be connected toward the second referenceterminal 2L The rectifier devices will thus. begin to conduct currentwhen the second reference terminal 2| is less negativethan the voltage at the variabletap 15. An output voltage similar to the firstor fourth output voltage which will vary 'directly'with the signal voltage variations for values less than the first reference voltage value and which will stay substantially constant at a given value for voltages greater than the first. reference voltage value may. then be obtained betweenthe interconnected positive terminalsand the output terminal which isat the point. of interconnection between the rectifier cathode and the impedance device in the appropriatebranch circuit. Also, an output voltage sin iilartov the second or. third output voltage which remains substantially constant at a given voltage value for signal voltage values less than the first reference voltage and thereafter varies inversely withthe signal voltage values for values thereof greater than the value of the first reference voltage may be obtained between a negative terminalof the reference direct voltage source and the output terminal in the other branch path which is at the point .of interconnection between the rectifier anode and the impedance device. Thus, this inverted, circuit would give voltages having'thesame characteristics as the circuits of Figures land 2.

'lhetaps 20, 2|, 22, 3t andfil on the resistance is. have been shown as beingvariable to depict that variations in the potentials obtainable therefrom are .-within the. contemplation .of the invention By ,varying the tapiil, the first out- 8 put voltage 61 and the reference voltageea, will vary. Variationof thetap 2i will changeallof the voltages except the signal voltage .es. Variae tion of the tap 3'! will vary the point at which the grid cl becomes negative relative to cathode 46, and hence will alter the curve of the third output voltage 63. Variations in 22 and .36 taps will effect variations in the thirdandfourth output voltages es and (24.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by Way of example and that numerous changes in the details of construction and the-combination and arrangement of parts may be resorted to Without departing from the spirit and the scope of the invention as hereinafter claimed.

We claim:

1. A voltage splitter comprising, a variable input source of a direct voltage having first and second terminals, a source of reference direct voltage having first and second terminals, the voltage between said first and second reference voltage terminals being in the same sense as the voltage between said first and second input .voltage terminals, means to interconnect saidfirst terminals, first and second paralleled branch paths interconnecting said second terminals, said branch paths each including a rectifier device and an impedance with the rectifier devices being reversely connected relative to the impedances, first and second output terminals connected to said first and second branch paths, respectively, whereina first output voltage is developed between said first output terminal and a terminal connected to said reference voltage source, and a secondoutput voltage developed between said second output terminal and a terminal connected to said reference voltage rource.

2. A voltage splitter comprising, a variable input source of a direct voltage having first and second terminals, a source of reference direct voltage having first and second terminals, the voltage between said first and second reference voltage terminals being in the same sense as the voltage between said first and second input voltage terminals, means to interconnect said first terminals, first and second paralleled branch. paths interconnecting said second terminals, said branch paths each including an impedance and a rectifier device with the anode of oneof the rectifier devices being connected to one of the impedances and thecathode of the other rectifier device being connected to the other of the impedances, first and second output terminals connected to said first and second branch paths, respectively, wherein a first output voltage is developed between said first output terminal and. a terminal connected to said reference voltage source, and a second output voltage is developed between said second output terminal and a terminal connected to said reference voltage source.

3. A voltage splitter comprising, a variable input source of a direct voltage having first and second terminals, a source of reference direct voltage having first and second terminals, the voltage between said first and second reference voltage terminals being in the same sense as the voltage between said first and second inputvoltage terminals, means b0 interconnect said first terminals, first and second paralleled branchpaths interconnecting said second terminals, said branch paths each including an impedance and a rectifier device with the impedances-in the two branch paths being connected to opposite elements of the rectifier devices, first and second output terminals connected to said first and second branch paths, respectively, wherein a first output voltage is developed between said first output terminal and a terminal connected to said reference voltage source which terminal is negative relative to said second reference voltage ter minal, and a second output voltage is developed between said second output terminal and a terminal connected to'said reference voltage source which terminal is positive relative to said second reference voltage terminal.

4. A voltage splitter, comprising a variable source input direct voltage having negative and positive terminals, a source of reference direct voltage having a first terminal and a second terminal positive relative to said first terminal for defining a reference voltage, means to interconnect a terminal of each of said sources, first and second paralleled branch paths interconnecting said positive and said second terminals, said branch paths each including an impedance and a rectifier device, one of said rectifier devices having a control element, first and second output terminals connected to said first and second branch paths, respectively, at the juncture of the impedance and the rectifier device With the rectifier devices reversely connected relative to the associated impedances, and means to apply to said control element a voltage representative of the input voltage wherein a first output voltage is developed between said first output terminal and a terminal connected to said reference voltage source, and a second output voltage is developed between said second output terminal and a terminal connected to said reference voltage source which voltage approaches asymptotically a predetermined value as the input voltage approaches one end of its range of variations.

5. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminals, a source of reference dire ct voltage having a first terminal and a second terminal positive relative to said first terminal for defining a reference voltage, means to interconnect a terminal of each of said sources, first and second paralleled branch paths interconnecting said positive and said second terminals, said branch paths each including an impedance and a rectifier device with the rectifier devices being reversely connected relative to said impedances, one of said rectifier devices being nonlinear, first 3 and second output terminals connected to said" first and second branch paths, respectively, wherein a first output voltage is developed'be tween said first output terminal and a terminal connected to said reference voltage source, and a second output voltage is developed between said second output terminal and a terminal connected to said reference voltage source, whereby said first output voltage varies in accordance with signal voltage variations for signal voltage variations less than said reference voltage value and whereby said second output voltage varies as a nonlinear function in accordance with signal voltage variations for signal voltage values greater than saidreference voltage value.

6. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminais, a source of reference direct voltage having a first terminal and a second terminal positive relative to said first terminal for defining a reference voltage, means to interconnect said negative and said first terminals, first and second paralleled branch paths interconnecting said positive and said second terminals, said branch paths each including an impedance in series with a rectifier device with the anode thereof being connected toward said positive signal voltage terminal, first and second output terminals connected to said first and second branch paths, respectively, said first output terminal being connected at the juncture of the impedance and th rectifier anode in the first branch path, and said second output terminal being connected at the juncture of the impedance and the rectifier cathode in the second branch path, wherein a first output voltage is developed between said first output terminal and a terminal connected to said reference voltage source, and a second output voltage is developed between said second output terminal and a terminal connected to said reference voltage source, whereby said first output voltage varies in accordance with signal voltage variations for signal voltage variations less than said reference voltage value and whereby said second output voltage varies in accordance with signal voltage variations for signal voltage values greater than said reference voltage value.

7. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminals, a source of reference direct voltage having a first terminal and a second terminal positive relative to said first terminal for defining a reference voltage, means to interconnect 'a terminal of each of said sources, first and second paralleled branch paths interconnecting said positive and said second terminals, said branch paths each including an impedance and a rectifier device with the rectifier devices being oppositely connected relative to the associated impedances, first and second output terminals connected to said first and second branch paths, re

" spectively, wherein a first output voltage is develcped between said first output terminal and a terminal connected to said reference voltage source,'and a second output voltage is developed between said second output terminal and a terminal connected to said reference voltage source, whereby said first output voltage varies in accordance with signal voltage variations for signal voltage variations less than said reference voltage value and then remains substantially constant at a given value for signal voltage variations greater than said reference voltage value, and whereby said second output voltage remains substantially constant at a given value for signal voltage variations less than said reference voltage value and varies in proportion to signal voltage variations for signal voltage values greater than said reference voltage value.

8. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminals, a source of reference direct voltag having negative, intermediate and positive terminals, first and second branch paths paralleled across said positive signal voltage terminal and said intermediate reference voltage terminal, additional connection means to interconnect said sources, said branch paths each including a rectifier device and an impedance device serially connected with first and second output terminals connected therebetween, respectively, said negative and positive reference voltage'terminals constituting third and fourth output terminals, respectively, said negative and intermediate reference voltage terminals having a first reference voltage developed thereacross at a value less than the maximum value of said signal voltmediateand positive terminals, first and second ,1

age, said intermediate and positive reference voltage terminals having a second reference voltage developed thereacross at value less than the maximum valu of said signal voltage, said rectifir devices being thermionic tubes having an on de a cathode, said impedance device in first branch circuit being connected to said anode of the thermionic tube therein, and said impedance, device in said second branch circuit i; ng connected to said cathode of the thermionic tube thereiirwherebv first output voltage is developed across said first and third output terinitials and a second output voltage is developed a cs saidsecond and fourth output terminals.

, 9. A signal voltage splitter, comprising a variab e source of signal direct voltage having negarectifierdevic and an impedance device serially connected witlrfirst and second output terminals tliierebetween, respectively, said rectiii ces being connected in the same sense, said, negative and positive reference voltage terininalsconstituting third and fourth output termini-1 1s, respectively, said negative and intermediate: reference voltage terminals having a first re erence voitagedeveloped thereacross at a value s th n thernaxifmum value of said signal voltage, sa d intermediate and positive reference voltagelterininals having a second reference voltage developed thereacross, said rectifier devices being th rznionictubes having an anode and a cathode, "id impedance device in said first branch circuit ng connected to, said anode of the thermionic tubetheren, and said impedance device in said sec nd branch circuit being connected to said on hodeoi thethermionic tube therein, whereby filstoutputvoltage is developed across said first and, third;Outputterminals which varies directly with the variations in said signal voltage up to deviant of the first reference voltage, and wherea, secblndoutput voltage is developed across Said d and, fourthoutput terminals which resnbstantially constant at a value equal to z Inams thejscond reference voltage for values of said signal voltage less than said. first reference voltage Willie "10, A signal voltage splitter, comp-risnig a variable source of signal direct voltage neg tes and positive terminals, a so reference direct voltage having negative, inter branch paths paralleled across said positive sig' voltage terminal and said intermediate renrence voltage terminal, means to interconnect twoterrninals of said sources, said branch paths each including a rectifier device and an iin .p e dance device serially connected with first and secondoutput terminals connected therehetv-Jeen, respectively, said rectifier devices being connected in, the same sense, said negative and positive reference voltage terminals constituting third and, fourth output terminals, respectively, said negative and intermediate reference voltage terminals having a first reference voltage de veloped thereacross which is less than the mash mum value of said signal voltage, said intermediate and positive reference voltage terminals having a second reference voltage developed thereacross, said rectifier devices being thermionic tubes having an, anode and a cathode, said impedance device in said first branch circuit ig connected to said anode of the thermionic tube therein, and said impedance device in said sseond branch circuit being connected to said cathode of the thermionic tube therein, one of said rectifier devices being a thermionic tube hav: ing a control grid, first and second grid biasing impedances serially connected between said posi: tive signal voltage terminal and said reference voltage source, and, means for connecting said grid to the juncture of said first and second grid biasing impedances, whereby, a first output voltage is developed across said first and third output terminals which varies in direct proportion as a substantially linear function of the variations in said signal voltage up to the value of the first reference voltage and stays substanth 15 constant at a value equal to said first reference voltfor signal voltage variations greater than said first reference voltage value, and second output voltage is developed ac second fourthoutput terminals which mains substantially constant at a value equal to'the second reference voltage for values of said signal voltage less than said firstreierence volt age value and varies in inverse proportion as a nonlinear function of the signal voltage for values of Nd signal voltage greater than said first reference voltage value.

mediate and positiveterminals, first and second branch. paths paralleled across said positive signal voltage terminal and said intermediate reference voltage terminal, means for intercom ne'cting said sources, said branch paths each including a rectifier device and an irnpeda. ce device serially connected with first and second on put terminals connected"therebetv/esn, respeciv vy a d e ativ a d os e e e e e volt" age terminals constitutingthird and fourth output terminals, respectively, said negative and intermediate reference voltage terminals having a first reference voltage developed thereacross, said intermediate and positive reference voltage tern'iinals having asecond reference voltage deiveloped thereacross, whereby afirst output voltage ,is developed across saidfirstv and third output terminals which, varies directly with the variationsin said signal voltage upto the value, of the first. reference voltage, and whereby a second output voltage is developed across said second and'fourth output terminals whichremains stantially constant at a value eomal to the second reference voltage for values, of. saidsignal voltage less than said. first reference voltage, valve,

12. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminals, a source of reference direct voltage havingv negative. inter mediate, and positive terminals, first and second branch paths paralleled acrosssaid-positive signal voltage terminal anclsaid intermediate reference voltage terminal, means to interconnect said sources, saidbranch paths each includinga rectifier deviceand-an impedance. device serially connectedwithfirst and secondfoutput terminals connected therebetween, respectively, said nega,- tive andpositive reference voltage terminalsconstituting third and fourth output terminals, respectively, said negative and intermediatereference voltage terminals having a first reference voltage developed thereacross, said intermediate and positive reference voltage terminals having a second reference voltage developed. thereacross, whereby a first output voltage is developed across said first and third output terminals which varies directly with the variations in said signal voltage up to the value of the first reference voltage and stays substantially constant at a value equal to said first reference voltage for signal voltage variations greater than said first reference voltage value, and whereby a second output voltage is developed across said second and fourth output terminals which remainssubstantially constant at a value equal to the second reference voltage for values of said signal voltage less than said first reference voltage value and varies inversely with the signal voltage for values of said signal voltage greater than said first reference voltage value.

13. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminals, a source of reference direct voltage having negative, intermediate and positive terminals, first and second branch paths paralleled across said positive signal voltage terminal and said intermediate reference voltage terminal, means to interconnect said sources, said branch paths each including a rectifier device and an impedance device serially connected with first and second output terminals connected therebetween, respectively, said negative and positive reference voltage terminals constituting third and fourth output terminals, respectively, said negative and intermediate reference voltage terminals having a first reference voltage developed thereacross, said intermediate and positive reference voltage terminals having a second reference voltage developed thereacross, whereby a first output voltage is developed across said first and third output terminals which varies in direct proportion as a substantially linear function of the variations in said signal voltage up to the value of the first reference voltage and stays substantially constant at a value equal to said'first reference voltage for signal voltage variations greater than said first reference voltage value, and whereby a second output voltage is developed across said second and fourth output terminals which remains substantially constant at a value equal to the second reference voltage for values of said signal voltage less than said first reference Voltage value and varies in inverse proportion as a substantially linear function of the signal voltage for values of said signal'voltage greater than said first reference voltage value.

14. A signal voltage splitter, comprising a variable source of signal direct voltage having negative and positive terminals, a source of reference direct voltage having negative, intermediate and positive terminals, first and second branch paths parallelled across said positive signal voltage terminal and said intermediate reference voltage terminal, means for interconnecting said sources,

said branch paths each including a rectifier device and an impedance device serially connected with first. and second output terminals connected therebetween, respectively, said negative and positive reference voltage terminals constituting third and fourth output terminals, respectively, said negative and intermediate reference voltage terminals having a first reference voltage developed thereacross, said intermediate and positive reference voltage terminals having a second reference voltage developed thereacross, one of said rectifier devices being'a thermionic tube having a control grid, first and second grid biasing impedances serially connected between said positive signal voltage terminal and said reference voltage source, and means for connecting said grid to the juncture of said first and second grid biasing impedances, whereby a first output voltage is developed across said first and third output terminals which varies in direct proportion as a substantially linear function of the variations in said signal voltage up to the value of the first reference voltage and stays substantially constant at a value equal to said first reference voltage for signal voltage variations greater than said first reference voltage value, and whereby a second output volt age is developed across said second and fourth output terminals which remains substantially constant at a value equal to the second reference voltage for values of said signal voltage less than said first reference voltage value and varies in inverse proportion as a nonlinear function of the signal voltage having a continuously decreasing rate of change for values of said signal voltage greater than said first reference voltage value.

15. A voltage dividing circuit including a signal direct voltage source, a reference direct voltage source, a first rectifier having a first cathode and a first anode, a second rectifier having a second cathode, and a second anode, a cathode resistor interconnecting said cathodes, an anode resistor interconnecting said anodes, means to apply a variable signal potential to said first anode from said signal direct voltage source, means to apply a reference potential to said second cathode from an intermediate terminal of said reference direct voltage source, connection means for interconnecting the negative terminals of said sources, a first terminal at said negative source terminals, a second terminal at the juncture of said second anode and said anode resistor, a third terminal at the juncture of said first cathode and said cathode resistor, and a fourth terminal at the positive end of said reference direct voltage source, said negative and intermediate reference voltage terminals establishing a first reference voltage and said intermediate and positive reference voltage terminals establishing a second reference voltage, whereby the voltage across the first and second terminals varies in accordance with the signal voltage variations for signal voltage values less than the value of the first reference voltage, and whereby the voltage across the third and fourth terminals remains substantially at the value of the second reference voltage for signal voltage variations less than the value of said first reference voltage.

16. A voltage dividing circuit including a signal direct voltage source, a reference direct voltage source, a first rectifier having a first cathode and a first anode, a second rectifier having a second cathode and a second anode, a cathode resistor interconnecting said cathodes, an anode resistor interconnecting said anodes, means to apply a variable signal potential to said first anode from said signal direct Voltage source, means to apply a reference potential to said second cathode from an intermediate terminal of said reference direct voltage source, connection means for interconnecting the negative terminals of 'said sources, a first terminal at said negative source terminals, a second terminal at the juncture of said second anode and said anode resistor, a third terminal at the junctureof said first cathode and said cathode resistor, and a fourth terminal at the positive end of said reference direct voltagesource, whereby a first out- 1.5 put voltage is obtained at the first and second terminals and a second output voltage is obtained at the third and fourth terminals.

17. A voltage dividing circuit including a nal direct voltage source, a reference direct voltage source, a firstreotifier havin a first cathode and a first anode, a second rectifier having a second cathode and a second anode, a cathode resistor interconnecting said cathodes, an anode resistor interconnecting said anodes, means to apply a variable signal potential to said first anode from said signal direct voltage source, meansto apply a reference potential to said sec- 0nd cathode from an intermediate terminal of said reference direct voltage source, connection 1? means for interconnecting the negative terminals of said sources, a first terminal at said negative source terminals, a second terminal at the juncture of said second anode and said anode resistor, a third terminal at the juncture of said first cathode and said cathode resistor, and a fourth terminal at the positive end of said reference direct voltage source, said negative and intermediate reference voltage terminals establishing a first reference voltage and said intermediate and positive reference voltage terminals establishing a second reference voltage, whereby the voltage across the first and second terminals varies directly as a substantially linear function of the signal voltage variations for signal voltage values less than the value of the first reference voltage and remains substantially constant at the value of the first reference voltage for variations of the signal voltage greater than the value of the first reference voltage, and whereby the voltage across the thirdand fourth terminals remains substantially at the value of the second reference voltage for signal voltage variations less than the value of said first reference voltage and varies inversely as, a substantially linear function of the signal voltage variations greater than the value of the first reference voltage.

18'. A voltage dividing circuit includ' nal direct voltage source, a reference age source, a first rectifier havin ode and a first anode, a second re second cathode and second anoe resistor interconnecting said cathod resistor interconnecting anodes, apply a variable signal is tial to anode from said signal direct v r means to apply a reference potential 0nd cathode from an intermediate-lie said reference direct voltage source, connection means for interconnecting the negative terminals of said sources, a first terminal at said negative source terminals, a second terminal at the juncture of said second anode and anode resistor, a third terminal at the juncture of first cathode and said cathode resistor, and a fourth terminal at the positive end or" said reference direct voltage source, said first recti r being a thermionic tube having a control g first and second grid biasing impedances serially connected between said first anode and a con nection to said reference voltage source having a potential more positive than said inter-mediate terminal, and means for connecting said to the juncture of said first and second grid biasing impedances, said negative and intermedi" ate reference voltage terminals establishing a first reference voltage and said intermediate and positive reference voltage terminalsestablishing a second reference voltage, whereby the voltage across the first and'second terminals varies di rectly as a substantially linear function of the signal voltage variations for signal voltage values less than the value of the first reference voltage and remains substantially constant at the value Of the first reference voltage for variations of the signal voltage greater than the value of the first reference voltage, and whereby the vol-t age across the third and fourth terminals remains substantially at the value of the second reference voltage for-signal voltage variations less than the value of said first reference voltage and varies inversely as a nonlinear function approaching a hyperbolic function of the s nal voltage variations over at least a partof he range of signal voltage variations greater than the value of the first reference voltage;

19. A voltage splitting circuit for deriving from a variable input voltage two unidirectionaloutput voltages which may vary in different ways independence onvariations in the input voltage, said circuit comprising means for establishing unid-irect-ionalreference potential, meansfor establishing a difference voltage comprising the dif- 'ference between a potential obtained fromthe input voltage and said unidirectional reference potential, first and second parallel connected branch circuits, means for connecting-said difference voltage across said paralleled branch circults, said branch circuitseach comprising a rectifier device and an impedance serially connected with first and second output terminals th'erebetween, respectively, one of said impedances being connected to the anode en'd o'f the associated rectifier device and the 'otlrerpfsaid impedances being connectedto the cathode end of the associated rectifier device, one 'of' saidputput voltages being obtained between said first output terminal and a terminal having a definable potential relative to said reference potential and'tn'e other output voltage being obtained'between said second output terminal and a terminal having a definable potential relative to said reference potential.

20. A voltage splitting circuit operable from a variable input voltage comprising means for establishing a unidirectional reference potential, first and second parallel connected branch circuits, means for connecting across said paralleled branch circuits a voltage representing the difference in potential between said unidirectional re'ference potential and a potential obtained from said input voltage, said branch circuits each comprising a rectifier device and an impedance serially connected with first and second output terminals therebetween, respectively, one of said impedances being connected to the anode end of the associated rectifier device and the other of said impedances being connected to the cathode end of the associated rectifier device, one of said output voltages being obtained between said first output terminal and a terminal havinga definable potential relative to said reference potential and the other output voltage being obtained between said second output terminal and a terminal having a definable potential relative to saidreference potential.

21. A voltage splitting circuit operable from a variable input voltage comprising means for establishing a unidirectional reference potential, first and second parallel connected branch circuits, and meansfor connecting acrosssaid paral-leled branch circuits a voltage representing the difference in potential between said unidirectional reference potential and a potential obtained from said input voltage, said branch circuits each comprising a rectifier device and an impedance serially connected with first and sec-- ond output terminals therebetween, respectively, one of said rectifier devices having a control element, one of said impedances being connected to the anode end of the associated rectifier device and the other of said impedances being connected to the cathode end of the associated rectifier device, one of said output voltages being obtained between said first output terminal and a terminal having a definable potential relative to said reference potential and the other output voltage being obtained between said second output terminal and a terminal having a definable potential relative to said reference potential.

22. A voltage splitting circuit for deriving from a variable unidirectional input voltage two unidirectional output voltages which may vary in different ways in dependence on variations in the input voltage, said circuit comprising means for establishing a unidirectional reference voltage, means for connecting said input and reference voltages in opposition to establish a difference voltage, first and second parallel connected branch circuits, and means for connecting said difference voltage across said paralleled branch circuits, said branch circuits each comprising a rectifier device and an impedance serially connected with an output terminal at the juncture thereof, one of said impedances being connected to the anode end of the associated rectifier de vice and the other of said impedances being connected to the cathode end of the associated rectifier device, one of said output voltages being obtained from the output terminal in one branch circuit and a terminal connected to the reference voltage source and the other output voltage bein: obtained from the output terminal in the other branch circuit and a terminal connected to the reference voltage source.

23. A voltage splitting circuit for deriving from a variable unidirectional input voltage two unidirectional output voltages which may vary indifferent ways in dependence on variations in the input voltage, said circuit comprising means for establishing a unidirectional reference voltage, means for connecting said input and reference voltages in opposition to establish a difference voltage, first and second parallel connected branch circuits, and means for connecting said difference voltage across said paralleled branch circuits, said branch circuits each comprising a rectifier device and an impedance serially connected with an output terminal at the juncture thereof, one of said impedances being connected to the anode end of the associated rectifier device and the other of said impedances being connected to the cathode end of the associated rectifier device, one of said output voltages being obtained from the output terminal in one branch circuit and a first terminal connected to the reference voltage source and the other output voltage being obtained from the output terminal in the other branch circuit and a second terminal connected to the reference voltage source, the connections of the branch circuits to the ref erence voltage source being at a potential intermediate the potentials of said first and second terminals.

JAY W. PICKING. WALTER J. BROWN.

REFERENCES CITED UNITED STATES PATENTS Name Date R gers "aw-a e, Dec, 28, 1943 Number 

